Training Simon
by Catreadsbooks
Summary: Post CoLS: Isabelle is worried now that Simon no longer has the Mark of Cain to protect him, so she decides to train him.
1. Chapter 1

So now that Simon has lost his Mark of Cain, Raphael is after him and Maureen is even more crazy than usual, I think that Simon should get some basic Shadowhunter training – or something similar - to be able to really defend himself and who is better suited than Isabelle? I'm sure she worries about Simon, too.

This is for all the Sizzy shippers

**Training Simon **

Isabelle wraps her whip around her arm. "Ok, I think that's enough training for tonight." Clary breathes a sigh of relief and wipes some sweat off her forehead. She sprawls down on a mat and takes deep breaths. Izzy shakes her head and nudges her red haired friend with her trainer. "Oh come one, that wasn't so bad, was it?" Clary only rolls her eyes, "I'm looking forward to the day when Jace can train me again, you are ruthless, Iz." Isabelle sits down next to her and shakes her head, smiling. "You are only saying this because you used to sneak kisses from Jace while he was training you." "Hey, that's so not true!" The dark haired Shadowhunter only grins knowingly. "Sure… So, how is it going for you and Jace?" Clary groans and covers her sweaty face, "Don't ask, Iz! I'm so glad he's back but this whole Heavenly Fire issue is so freaking frustrating! We can barely touch each other…" She throws Isabelle a dirty look when she sees her friend smirking. "Isabelle! Not like that!" Clary blushes and picks at her sweatpants. Izzy looks at her expectantly but Clary doesn't elaborate. Instead, she decides to make her friend uncomfortable for a change. "What about you and Simon? Have you talked to him? Are you together now?" Isabelle scowls, lies down next to Clary and stares at the ceiling, "We haven't talked much since Ireland. He and Becky are busying convincing their mother that he is not evil." Clary grabs Izzy's hand, "Are you afraid he will reject you?" "What? No," says Isabelle indignantly. Clary pushes herself up on her elbows and looks at her friend, "So what is stopping you? You want to be with him, he wants to be with you. Just talk to him, Izzy because like I told you before, Simon won't make the first step. It has to be you."

Isabelle gets up again and starts putting away the training weapons, muttering under her breath. Clary chuckles when she hears "Stupid Simon" and "Stupid feelings" coming out of Izzy's mouth and gets up to help her tidy the training room.

"Tomorrow, same time?" Isabelle asks once they are done. Clary shakes her head, "I can't. My mom wants me to help with the wedding, maybe tomorrow mor –" Clary's cell phone rings. "Hang on, it's Simon. – Hi!" "Clary, are you at the Institute?" Simon's voice sounds worried. Clary frowns, "Yeah, what's going on?" Simon's breath is irregular, "I think I'm being followed and since I no longer have the Mark -" He lets his sentence drift off. "Okay, where are you right now? Iz and I will come to help." Isabelle's eyes widen and she tugs on Clary's T-shirt. "What's happening? Why does Simon need our help?" she whispers frantically. Clary waves her hand and turns away from her. "What was that? Where are you?" "I'm heading to the Institute." Clary turns to the door and motions Isabelle to follow her. "Ok, don't worry. We're on our way out now. We got this." She hangs up, "Simon thinks he is being followed. He's on his way here now." Isabelle lets out an unladylike curse and storms to a cabinet holding seraph blades. "He hasn't got his Mark!" Clary nods, "I know –" Isabelle rushes out of the room, putting two blades into the back of her sweatpants and running down the corridor before Clary can finish her sentence. "Hurry up, Clary! He's completely defenseless!" She hurries after Izzy, "He's a vampire, Iz. He can handle himself." Isabelle arrives at the elevator and stabs the call button. "Strength isn't all, Clary. He doesn't know how to defend himself properly. You don't need to use brute force to defeat an opponent. Sometimes it only takes the right strategy." "Well, Simon is good at strategy; he plays all these computer games." Isabelle glares, "This isn't the same, Clary. We are talking about Simon's life! Damn it, why isn't this elevator moving faster?" She kicks the metal, clearly frustrated.

The car finally arrives and Isabelle drags Clary inside. Once they are in the nave of the church, the older Shadowhunter rushes down the aisle and throws the door open. A few seconds later she is down the steps and running down the path to the gates. Clary can only gape at Isabelle and quickly picks up her pace to keep up. "Iz, wait for me!"

Isabelle hears Clary's cry but ignores it, passing the gates and turning towards the busy street. She spots a lone, hurriedly moving figure a few hundred yards away. Although the sun has just set and bathed the streets in blueish light, she still recognizes Simon's dark hair and his lanky built. She breathes a tiny sigh of relief and runs to met him. Simon is nearly knocked off his feet when Isabelle's arms wrap around his neck and squeeze him tightly. "By the Angel, you are alright!" "Uh yeah," he mumbles into her neck, breathing in her gardenia smell and sweat. "I think I lost them after they realized that I was going to the Institute." Isabelle steps back but she is still standing rather close. Simon can feel her breath on his skin and see the vein which is pumping steadily in her neck. "You had me worried." He runs a hand through his hair, "Yeah, sorry, I – "She brushes her cool hand over his forehead." You're no longer invincible, Simon. You have to be careful from now on. Did you see who was following you?" Simon takes a deep breath although he doesn't need to, "I'm pretty sure they were some of Raphael's guys." Izzy gapes at him and even Clary, who has no reached them, looks worried. "Raphael wants you dead, Simon, "Clary remarks and he rolls his eyes."Gee, thanks, Clary. I didn't know."

The sky darkens further and Clary shivers. "We should go back to the Institute", she turns to leave. "I can't." She mentally slaps herself; of course he can't enter hallowed ground. Isabelle gives her an encouraging smile. "Just go back to Jace, I'm sure he's waiting for you. Simon and I will go to his apartment and I'll keep him company there." Simon looks surprised, "You will?" "Yes, let's go." Clary hugs her friends quickly. "We'll be back tomorrow morning at 9, ok?" The redhead nods, "Be careful." "I'm sure Isabelle will take good care of me," Simon reassures his friend. Isabelle gives Clary a tiny smile and waves.

Simon and Isabelle turn to head to the nearest subway station. Their hands occasionally brush against each other and after a while, Simon takes her hand into his and laces their fingers together. Isabelle looks at him out of the corner of her eyes and sees him smiling, staring straight ahead. "I was really worried that something had happened to you, Simon." He stops and takes her other hand into his, "I'm okay, Isabelle. I'm a vampire, not some helpless mundane." She sighs, staring at his slightly larger hands. "I'd feel better if you let me give you a few training lessons so that you could defend yourself." His eyes widen and Simon is speechless for a moment, "You want to train me? Like a Shadowhunter?" Her cheeks turn a slight rose color, "A few basic defense moves couldn't hurt." In an act of bravery, Simon tips her chin up and looks at her intently. "I cannot enter the Institute, Iz." She bites her lip and looks away. "The Shadowhunters have a training spot in Central Park, we could go there." He thinks about her offer and finally agrees, "Ok." Isabelle looks at him, clearly surprised by his answer, "Really?" Simon grins, one corner of his mouth going up before the other. "Yes, I will let you train me but in return you will go out with me to watch at least one Star Wars movie." Her heart beats faster in her chest, "Take me out? On a date?" He nods sheepishly. Isabelle relaxes and lets go of one of his hands, tugging on the other. "Sounds like a plan. Let's hurry back to your apartment; I need to use your shower. We left as soon as Clary got your call and I feel a bit cold." Simon wordlessly takes off his leather jacket and drapes it over her shoulders. "Thank you," Izzy mumbles while wrapping herself up in his scent. He takes her hand again and they enter the subway station. The rest of their journey passes in a comfortable silence until they reach his apartment. "You will kick my butt tomorrow, won't you?" Izzy laughs. "I'll go easy on you in your first lesson." Simon looks doubtful but shrugs. "I will get you a towel and some of my clothes." She nods and sits down at the edge of the sofa. Simon returns after a few moments, hands her the clothes and motions to his room, "I'll be inside – waiting for you." "Thank you, Simon."

She quickly showers and enters his room somewhat nervously. It's almost completely dark but Isabelle can see Simon sitting on his bed, his hands gripping his knees tightly. "I ordered some food for you, from Taki's. Should be here soon." She sits down next to him and brushes her finger over his left wrist, "Thanks." He clears his throat, swallowing nervously and then he turns to her. Isabelle's hair is slicked back and her face scrubbed bare. She looks younger which somehow relaxes Simon a little bit. His eyes roam over her figure, taking in the way his sweatpants cling to her hips and how her breath under his 'Made in Brooklyn' shirt is slightly uneven. "Your hair, it's still wet. You –" Simon stops, almost reaching out to push her a strand of hair behind her ear. "You should dry it unless you want to catch a cold." Isabelle bites her lip and his gaze flickers to her full bottom lip before looking into her dark eyes. Simon cups her cheek, smelling his shampoo on her and he leans closer. Only inches are separating them now but before Simon can close the gap between them, the doorbell rings. They both shoot to their feet. "It's your food." "Yeah, thanks, I got that." Isabelle turns away from him and silently curses the delivery guy. "I'll just… get it", Simon says awkwardly. She nods in agreement and points to her towel which is at her feet, "I'll dry my hair."

He leaves his room while clenching his fists to keep his frustration at bay. He mentally berates himself and almost growls at the guy who delivers Izzy's favorite food and some blood for him. Once he has paid, he slams the door shut and begins to spread the food on the couch table. After his work is done, Simon throws himself on the couch and rubs his hands over his face, trying not to think about what has nearly happened in his room.

Isabelle enters the living room to find a burger, her beloved smoothie and French fries spread out, "That looks delicious. How much do I owe you?" Simon looks up from his slouched position on the couch, his gaze still a bit frustrated. He shakes his head, "It's ok, my treat." She sits down next to him, gives him a grateful smile and fingers her hair which is now in a braid. "You ordered my favorite smoothie. That's really sweet. Thank you, Simon."

They both eat in silence, relieved that the tension that has built is finally fading. After their meals, Simon picks a movie and they watch, both sitting at a respectable distance, until Isabelle's yawns are as frequent as her blinks. They tidy the living room without many words and afterwards Izzy slips into the bathroom to get ready for bed.

Once back in Simon's room, a familiar sight greets her. Simon is sitting at the edge of his bed, clearly waiting for her. Isabelle steps out of Simon's sweatpants and smiles at his blush when he sees her naked legs. He shifts and gets under his covers, holding one end open for her. She quietly slips next to him and he immediately wraps his arms around her like he used to at Magnus's apartment. Isabelle presses a kiss to his cheek and curls against him, "Good night." He clears his throat, "Good night, Isabelle."

They fall asleep to the never-stopping sounds of New York City.


	2. Chapter 2

Sorry for the long wait - life got a little busy - and thank you for your reviews and the favorites. It's been ages since I've written more than a one-shot but I simply adore Simon and Isabelle and they deserve their HEA in a more rounded story.

**Before you read this chapter please go back to chapter one because I've edited it and added around 200 words.**

Hope you enjoy the second chapter of

**Training Simon **

The next morning the sky is gray with heavy raindrops pelting against Simon's window. Isabelle wakes up, the weak light shining on her black braided hair and making it seem like shimmering silk. She blinks twice before she realizes that she is lying on top of Simon, her legs tangled with his and her head on his chest. His slow but unnecessary breaths ruffle her hair and his hands rest on the small of her back, one of them close to her backside. Isabelle tries to roll out of his embrace but Simon only tightens his grip. "Stay," he murmurs huskily. Her breath nearly hitches but she catches herself. "Wake up sleepyhead; it's time to learn some cool defense moves." Simon groans and flips them over with his nose suddenly buried in her hair, "You smell nice." Isabelle's eyes widen, "Simon…" "Ok, I'm awake. In fact, I've been awake for almost an hour now." She rolls her eyes and tugs on his hair so that he's looking at her. His brown eyes which always remind her of chocolate stare back at her and her heart gives a tiny but not completely unwanted flutter. "You could have woken me up, you know. I'm used to rising early." Simon shakes his head, "No way. You were making these cute noises in your sleep and I liked watching _you_ for a change." Isabelle averts her gaze, "What time is it?" "Almost 7.30." He lets her go and sits up, "You can use the bathroom first, I'll make you breakfast." She nods and gives him a grateful smile, glad that they both are no longer affected by yesterday's sudden awkwardness.

After a quick and refreshing shower, Izzy steps out of the bathroom while opening her braid. She shakes out her hair and approaches Simon who is busy at the stove. His hair is mussed up from sleep and his pajama pants are low on his hips revealing a bit of pale skin between the waistband and his shirt. Isabelle's fingers itch to touch his skin but she holds herself back. "Something smells amazing", she tells him appreciatively. Simon stiffens for a split second and then relaxes again, "Damn, don't sneak up on me." She grins and rests her hip against the counter next to him, "You're just not focused. Once you've had a few training lessons with me, you would have heard me despite the sizzling pan." She pokes his side teasingly before she looks at the content of the pan. "Is that an omelet?" Simon nods and puts it on a plate, "Yeah. We don't have much food because Jordan often leaves without breakfast and I don't need to eat. We just had a few eggs and toast left, I hope that's okay." Isabelle takes the plate, "I don't mind, this looks delicious." Simon finally has a good look at her; her normally straight hair tumbles over her shoulders and her skin is slightly flushed from her shower. She is back in her training outfit which reveals a lot of her runes. He exhales and before Isabelle can sit down to eat her breakfast, her stops her with a hand on her wrist. "I think you forgot something." She looks at him quizzically. "Basia coquum" he says softly. Her eyes widen and her lips part involuntarily. Simon's gaze wavers between confidence and insecurity but before he can retract his bold demand, Isabelle steps so close to him that he can feel her chest rising against his. She gently sets down the plate on the counter to have both of her hands free. One sneaks behind his neck whereas the other rests on his shoulder. She lifts her head, looks at him with so much longing in her eyes that Simon takes a step back and bumps against the stove. His hands come to rest on her waist and then she is finally kissing him. Her soft, warm lips press against his and she runs her hand through his curls. Before Simon can bring Isabelle even closer to his body, she takes a step back and places a final gentle kiss on his lips, "Thank you for the omelet." Simon nods without being able to form any words. He watches how Izzy takes a seat at the small kitchen table where she digs in. He finally clears his throat, "I'm gonna take a shower." Isabelle arches an eyebrow at him but remains quiet.

She continues eating her breakfast and even starts with the dishes before Simon appears at her side again. Izzy bites her lip to keep herself from commenting on his long shower and finishes drying the pan. "The omelet was fantastic. I didn't know that you can cook." Simon shrugs and runs a hand through his damp curls, "My mum often had to work so she taught Becky and me." She reaches out to give his hand a comforting squeeze, "How are things with you and your mum?" He grimaces which makes Isabelle's chest tighten. "We're still working on it but it's slow, very slow." She nods, trying to understand how hard this must be for him but failing. "I hope everything will turn out ok." Simon clears his throat and to prevent himself from saying anything further, he grabs a dish towel and helps Izzy.

Once the apartment is clean, probably cleaner than it has been in a while, Simon and Izzy leave to meet Clary and Jace. They take the subway and slowly excitement starts to grow in Izzy's belly. She takes Simon's hand and swings their hands around. "You're in a really good mood, should I be worried?" Simon asks carefully. She grins and says teasingly, "Maybe." He pulls a face and Izzy quickly amends, "Kidding, you will be fine. Just don't listen to Jace and whatever he says, do _not _practice with him. If you need a guinea pig you ask me or Clary, ok?" He nods, looks ahead and barely suppresses a groan. Isabelle follows his gaze and her eyes land on Clary and Jace who are kissing in front of the Institute, "Are you jealous?" Simon gently pulls her to a stop and brushes his thumb over the hand he is holding, "No, Clary is happy with him so I am happy for my best friend." Isabelle looks at him searchingly and finally accepts his statement, "Ok, let's separate these love birds. They can make out when we are not present." They arrive at the Institute's gates. Izzy clears her throat and her brother slowly untangles himself from his girlfriend. "Ready to get your ass kicked, Lewis?" Jace asks cockily, his eyes glowing more golden than usual. Clary punches his shoulder and Isabelle glares at him, "The only one who might kick Simon's ass is me or Clary. You stay away from him, Human Torch, " she replies with her hands on her hips. Jace grins, "Relax Iz, I won't hurt your Simon." Simon blushes and Isabelle mutters a "You better not" under her breath. She squeezes his hand and addresses the others, "I'll quickly change into a new training outfit, give me 5 minutes." Simon nods, shuffles his feet and looks a bit uncomfortable to be alone with Clary whose hair is more unruly than usual and Jace who has a very smug look on his face although his skin is rather transparent at the moment. Clearly Clary and Jace have been working on the latter's heavenly fire issue.

Isabelle dashes into the Institute, not willing to leave Simon alone for long and bursts into her room. Despite all the mess, she finds the outfit she is looking for and quickly changes into it. Simon's leather jacket which he has given her the previous evening rests on her bed and although Isabelle has more than enough jackets to choose from, she picks it up again and slips it on. It smells like him and she has to suppress a small sigh. They have kissed – repeatedly now – Simon has drunk her blood which was one of the most sensual things Isabelle Lightwood has ever done and they have a movie date, but are they together? No. She is not sure how much longer she can stand this uncertainty.

Lost in thought she joins the others again and her hand captures Simon's of her own accord. The quartet takes the subway to Central Park and they reach the spot that is glamoured from the mundanes. Isabelle widens her stance and fixes her gaze on Simon who has started to look a bit worried, "Ok, here is what you need to know. You don't need brutal strength or actual weapons to win a fight." Jace nods. "You can use your elbows, knees, feet, hands, even your head." Isabelle touches Simon's forehead. "If you use your head the right way, you can knock your opponent out. Same with the back of your head. A trick that we girls prefer is a good kick to the groin –" Simon and Jace grimace – "Or a kick against the knee, preferably the inside. Your attacker will go down and allow you to have a few precious moments that can be all that you need to escape. Because that's what you want to do, put your attacker out of commission so that you can escape. You don't beat him or her into a bloody pulp, you just get the hell out of there. Call the Institute and we might be able to take care of the rest. Ok?" Simon nods. Isabelle give him a slight smile. "Alright, first Jace and I will show you how to get out of a headlock. Jace?" The golden haired Shadowhunter groans, "You just _had to_ start with that!" She grins, "I'll go easy on you, promise." Jace grumbles and gets behind Isabelle. He wraps his left arm around her neck, his feet set apart for balance. Isabelle's one foot steps behind him, she ducks, kicks his groin, puts her other hand under his nose and presses Jace's head backwards. He falls and lands on his backside. Izzy nods, "Ok, that's one way to do it. When you put your hand right under your attacker's nose, you change their center of gravity. Let me show you something." She waves Simon over to her and puts her hand under his nose, "Try to walk now." Simon takes half a step and then tips backwards. "See? Easy as that. Now, I'll show you another way to get out of a headlock. Jace?" They take their position again and this time Isabelle explains her moves, "Take the hand that is behind your body, put it on the shoulder that is between your heads and just push him forward." She demonstrates and Jace is on the ground again. "Whoever attacks you will be afraid to land on their face so they will let go of you. Wanna give it a try or do you want to see another move?"

Simon opts for another move and Isabelle and Jace demonstrate how to get out of a chokehold. After Jace is once again on the ground, he complains, "I think you're having way too much fun with this, Iz. Let him practice with Clary now."

So Simon and Clary practice the moves, following instructions from either Isabelle or Jace.

The Shadowhunters go through even more defense techniques when Clary suddenly interrupts them, "I'm sorry guys, but I have to leave now. My mum needs me for her wedding preparations." She gives an apologetic shrug. Jace wipes away some sweat and wraps an arm around her, "I'll take you to the subway. Alec has been alone far too long, he needs some brotherly support." They say their goodbyes and then Simon and Isabelle are alone again.

Simon watches how Isabelle brushes away a few damp strands of her dark glossy hair. He inhales and the sweet smell of her sweat hits his nostrils. Her breathing is slightly elevated and Simon has never seen her so alive, so beautiful. He swallows and winces when his fangs pierce his bottom lip. He quickly licks his blood away before he turns to Isabelle, "What now? Are we done for today?" Isabelle chuckles softly, "No, let's go through all your defense moves again and then I'll show you a few others."

The vampire and the Shadowhunter fake-fight and Isabelle is surprised how fast Simon has learned the moves. She praises him for a clever combination of two techniques and finally he manages to toss her to the ground. Simon is leaning over her and his arm is slightly pressing against her windpipe. Their faces are only inches apart and Simon feels how her breath washes over him. His gaze flicks between her parted lips and her dark eyes which stare back intensely. "Good", Izzy whispers and Simon lets go, standing up and reaching out a hand to her. She accepts his help and is now in standing in front of him with a vulnerable expression on her face.

"What are we doing, Simon?" Isabelle asks breathlessly. He frowns, "What do you mean?" "This," she points from her to him and back, "Us, you and me?" Simon's frown deepens and he looks around helplessly, "I'm not sure, Isabelle." She gives a little huff, "Do you like me?" His spine straightens and he looks at her, his gaze filled with emotions Isabelle cannot quite read, "Yes, of course I like you!" She steps closer to him and suddenly he has difficulties focusing on anything else than Isabelle. Her scent lays itself like a blanket around him and Simon takes an unnecessary breath which only enhances everything. Her deep brown eyes stare into his and she quietly murmurs, "I like you, too. In fact, I more than just like you. You are under my skin and no matter what I do, I just cannot get rid of you, don't want to get rid of you in fact. I've never – I've never felt like this before and I'm a bit afraid because my heart feels very fragile around you." Simon pulls her even closer to him and brushes a hand over her cheek, "Are you saying that you are in love with me?" A blush almost explodes on her face and Simon feels her blood warming up her face. Isabelle looks down for a short moment and when she looks up again, she looks like the Isabelle he is used to. "Yes, that's exactly what I'm saying. I'm in love with you," she boldly admits. "Can you now please say that you are in love with me too, kiss me and be my boyfriend?" Simon grins her favorite smile, the one where first one corner of his mouth lifts before the other. He nods and tips her face back, "I'm in love with you, too, Isabelle. I've been in love with you for a while now." She beams at him but Simon quickly covers her smiling mouth with his own. He carefully nips at her bottom lip and when he feels her sink against his body, he knows that he will always remember this training lesson.

The end

I might write a 'sequel' about Simon and Isabelle's movie date that I mentioned in the first chapter.


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